Skewing arrangement for gantry frames



Jan. 2, 1945. R, W Cms-r 2,366,598

SKEWING ARRANGEMENT FOR GANTRY FRAMES Filed oct. a, 1943 2 sheets-sheet 1 INVENToR. Poes/er MA C//sr Jan. 2, 1945. R. w. cRlsT SKEWING ARRANGEMENT FOR GANTRY FRAMES Filed Oct. 8, 1943 2 Sheets-Sheet 2 INVENTOR. /FOBEPT W C @157' im Hmm? Patented Jan. 2, 1945 y UNETED? SKEWING ARRANGEMENT Fon GANrRY i FRAMES Robert W; Crist, Cleveland, Ohio, assignor to The Wellman Engineering Company, Ohio, a corporation of Ohio Cleveland, I

application october s, 1943, serialNo. 505,439

s 7 Claims.

This invention relates toa skewing arrangement` for the gantry -ira-mes of ore` unloaders, cranes, hoists, traveling trolleys; `and `the like, Where it is necessary or ydesirable to move either end of the frame `on the track while the other end is held stationary or to move either end at a `faster or `slower speed than the opposite` end is moved. I s

The principal object of the invention is to provide a skewing arrangement for gantry frames with provision for compensating for the relative foreshortening of the center line of the frame as compared to the track gauge, said arrangement being adapted for any stiff leg gantry frame.`

Occasionally the tracks of an unloader opposite a boat to be unloaded are on a curveso that the stii leg gantry frame is `not in line with the hatch of the boat, making it necessary to provide complicated mechanism to bring the supers structure of the unloader inline 'with the hatchway. It is one of the objects of the presentinvention to be able to skew the `gantry frame by 'a simplified mechanism `so that the frame of the uploader can be readily brought into align-v ment with the hatch of the boat.

It frequently happens that the distance between the rails or" the runway on which the unloader, crane, etc. runs does not remain constant but may shift to a greater or lesser span due to loads, soil conditions, etc., and it is a further object of this invention to provide a stiff frame with its traveling wheels, trucks and sills arranged in a manner to compensate for this variation in runway span, thus eliminating excessive wearson the flanges of the track wheels and rail heads, and preventing derailment or, if not derailment, undue stresses in the stili frame.

y A further object of theinvention is to provide an independent drive with control` for each end of the machine, thus eliminating Vthenecessity of providing and maintaining aline or squaring shaft with its attendant gears, brackets,vcou plings, etc. extending across the fulllength of the stiff frame to connect `to the track wheels i at each end. I

A still further object is to eliminate all motors, control and machinery (aside from the motors of the independent drive for each end of the machine) for skewing where skewing is necessary or desirable, `since the skewing motion is accomplished by the travel motors through the controlled unequal movements ofthe ends of the iframe. Thus the travel motors serve a` dual purpose. I

AIn the drawings I haveshown a simpliiied application of the invention. the gantry frame shown being adaptable for any of the purposes mentioned,above,` it being understood that the number of supporting wheels may be increased as may be required to carry the load, and, where necessary, two rails may be provided at each end in place of the single railshown at each end of the gantry frame.1 s

s In the accompanying sheets of drawings,

Figi is a side elevation showing the gantry frame mounted on four wheels for traveling on a runway consisting of two parallel rails, it being understood that the rails need not necessarily be straight but may be curved to the same center ;V I `Pigna is a view of one end of the gantry frame; I lc'ig.` 3 is a view of the Opposite end; Fig. 4 is a-plan view of the gantry frame on `the runway in normal position with its center fthe runway. l

Referring now to the drawings, Ill s represents the gantry frame braced to form a rigid structure. The frame here shown `has gantry legs II. The lower ends of the legs are` `connected togetherat one end,v which, for convenience, will be referred to as the front end, by a sill I2, and at the other or rear end by a sill I3. y The frame is supported on twol truck sill members, the truck sill at the feront end being designated I4 and the truck sill vat the rear endvbeing designatedpl,

leach truck sillA beinghere shown mounted on wheels I6 traveling on rails I1, it being remembered that a simplied showing only is made and that the number` of rails and wheels may be variedas necessity recuiires.` If desired, the gantry legs can be omitted,lleaving only a stii rectangular framewhich is supported on the truck sills. A I f- A simple driving unit I8 is shown` at one end of each truck sill, each driving unit consisting of a motor connected to a wheel I6 through suit able shafts and gears. The motors are independ- ,entlycontrolled each having a, separate controller (not shown) `The gantry framel is supported on the truck s `sills in the following manner: Secured `to the I .lower end` of each leg Il is asrnoothlyl finished and well lubricated skew plate 19. .The skew plate `IS) rests upon a similar'smoothly finished and `well lubricated bui-,smaller skew plate 2li,` therebeing between the skew plates I9 and 2B a free sliding surface. VThe entire weight of the zgantry frame `and any Asuperstructure mounted Athereon is carried `on these four sliding surfaces.

Each of the four skew plates 20 is preferably made to rest on a ball or equivalent device to insure equalized pressure between the skew plates la and 20. The four balls or equivalent devices of the skew plates 2U engage in socketed members 2| which are secured to the truck sills I4 and I5 near .Opposite ends thereof.

A straight king pin 22 (see Fig. 3) passes through the frame sill I3 and through the truck sill I5. of both sills and forms a rigid centering and pivot point and transmits the driving force for this end of the frame. It will be keyed in one sill and bushed'in the other, as shownv at 22a in Fig. 3, thus lending stability to the truck frame, holding it in upright position.

At the opposite `or front end of the frame is an offset pin 23 which passes through the frame sillr I2 near .the center thereof and through the truck sill I4. It is mounted in bushings 23a (see Fig. 2) in the frame sill and in similar bushings in the truck sill so that it will be free to swing to compensate for the relative foreshortening of the center line of the frame as 'compared to the track gauge and at the saine time lend Vstability to the truck sill as well as transmit the driving force from the truck sill to the frame. It will be noted that the lower end of the pin 23 is mounted centrally of the truck sill I4 while its upper end passes through the frame sill I2 at one side of its center line equal to' approximately one-half thedistance of the offsetting of the upper end of the pin with respect to the lower end.

`When the gantry and its superstructure are traveling along a straight track, both motors I8 will be operated at approximately the same speed. However, when it is desired to skew the frame I 0, one motor is slowed'downwitlr respect to the other, or, if one of the motors is not operating, the skewing can be done by operating the other motor either in forward or in reverse, depending upon the direction in which the frame is to be skewed, until the desired extent of skewing is obtained. It will be noted that as the skewingy occurs the plates I9 secured to the lower ends of the legs II will slide smoothly over the lower plates 20. The eiT-ect of this skewing is to foreshorten the frame I relative to the track span, and this foreshortening is compensated for by the oiset pin 23; It will be seen that Fig. 4 shows j the frame before the skewing and Fig. shows the frame after the skewing, the extent of foreshortening being equal to the distance between l the lines 24 and 25 indicated in Fig. 5. i

Thus it will be seen that my invention is admirably adapted for ore unloaders, traveling cranes, andthe like, and is useful in any case where skewing lof the gantry frame is desirable. Likewise, if the machine or equipment' provided with the invention is adapted to travel on tracks Whose gauge is greater orless than normal, the inequality in track gauge is automatically compensated for by the free lateral movement of the truck sill I4 relative to sill I2 vof the frame.

Likewise, it will be seen that by providing the two operating motors on the truck sills at opposite ends of the gantry frame, all other mechanism for skewing the gantry frame is eliminated. i

rFrom the foregoing it will be obvious that the objects stated in the early part of the specification are very eiectively attained by the present invention. It is to be remembered that a. simpliiied arrangement only is illustrated, the same, however,'showing the preferred construction, but I do not desire to be conned to the precise de- This pin is located on the center line tails shown but aim in my claims towcover all modifications which d0 not involve a departure from the spirit and the kscope of the invention.

Having thus described my invention, I claim: l

1. A gantry including a frame and truck sills with respect to which the frame is movably supported, .the truck sills having track-engaging wheels and means for skewng'the frame with respect to the sills, said means comprising a. vervtically disposed straight pin connecting one end with relatively slidable putes on the frame and sills by which the frame is movably supported 0n thesills, and means comprising an`offset pin having vertically disposedportions at one' end of the frame and connected to one of the truck sills and a, vertically disposed straight pin at the other end of the frame and connected t0 the other truck `sill for causing the frame to assume a skewed position with respect to the'sills, the sills having trackiengaging wheels, the second-mentioned endy of the frame being always positively centered by the straight pin on the track rfor the corresponding truck sill. j

3. A gantry including a frame, truck sills and wheels carried by the truck sills, said frame having plates engaging and slidable with respect toy similar plates on the truck sills, whereby the frame is movably supported on the trucksills, a straight pin connecting one end of the frame to a truck sill, an offset pin connecting the other end of the frame to the opposite truck sill, and means for skewing the frame with respect to the truck sills, the latter having track-engaging wheels, the iirst-mentioned end of the frame being always positively centered by the straight pin on the track for the corresponding truck sill.

4. A gantry including a frame, truck sills and wheels carried by the truck sills, said frame having platesengaging and slidable with respect to similar plates on the truck sills vwhereby the lframe is movably supported on the truck sills, a straight pin connecting one end of the frame to a truck sill, an offset pin connecting the other end of the frame to the oppositevtruck sill, and a separate motor connected to a wheel of each truck sill so that one truck sill may be moved relative to the other to cause skewing of the frame on the truck sills, the latter having track-engaging wheels, the first-mentioned end of the frame being always positively centered by the straight pin on the track for the corresponding truck sill.

5. A gantry including a frame and truck sills withrespect to which the frame is movably supported, and means for skewing the frame relative to the truck sills, said means comprising a vertically disposed straight pin connecting one end of the frame to a truck sill and an offset pin connecting the other end of the frame tothe opposite truck sill, said oiset pin having oiset vertically disposed portions, the straight` pin being secured lin one member and bushed in the other and the offset pin being bushed in both members, the

truckv sills having track-engaging wheels, theY iirst-mentioned end of the frame being always positively centered by the straight pin on the track for the corresponding truck sill.

6. A gantry including a frame and two truckl sills with wheels carried thereby, a straight pin' connecting the center of` one end of thegantry frame to one truck'sill, an offset pin connecting the other end of the gantry frame near the center thereof to the opposite truck sill, and means for supporting the lower side of each end of the gantry frame on the corresponding truck sill, the truck sills having track-engaging Wheels, the first-mentioned end of the frame being always positively centered by the straight pin on the track for the corresponding truck sill.

7. `A gantry including a frame and two `truck sillsv with wheels carried thereby, a straight pin n connectingthe center ofv one end of thegantry t frame to one truck sill, an offset pin connecting the other end of the gantry frame near the center thereof to the opposite truck sill, and means for supporting the lower side of each end ofthe gantry frame on the corresponding truck sill,

said means comprising plates carried by each end of the gantry frame and engaging corren sponding `plates carried by the truck sills, the e latter having track-engaging wheels, `thei'lrstmentioned end of the frame being always `positively centered by the straight pin on the track for the corresponding truck sill.

ROBERT W; CRIST. 

